Sticky sessions in HLD - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

What is the primary purpose of sticky sessions in load balancing?

Sticky sessions are used in load balancing to:

A Ensure a user is always routed to the same server during a session

B Distribute user requests evenly across all servers without preference

C Encrypt user data during transmission between client and server

D Automatically scale the number of servers based on traffic

💡 Hint

Think about user experience consistency during a session.

Sticky sessions ensure that a user's requests go to the same server to maintain session data consistency.

❓ Architecture

intermediate

Which component is essential to implement sticky sessions in a web application architecture?

To implement sticky sessions, which component must be configured to track and route user requests?

A Database replication system

B Content Delivery Network (CDN)

C Load balancer with session affinity enabled

D Firewall with IP filtering

💡 Hint

Consider which part directs traffic to servers.

The load balancer must have session affinity (sticky sessions) enabled to route users consistently.

❓ scaling

advanced

What is a major scalability challenge when using sticky sessions in a distributed system?

Sticky sessions can cause which problem when scaling web servers horizontally?

A Data loss because sessions are stored in a centralized database

B Increased network latency due to session encryption

C Automatic server shutdown due to session conflicts

D Uneven load distribution leading to some servers being overloaded

💡 Hint

Think about how sticky sessions affect load balancing fairness.

Sticky sessions can cause some servers to get more traffic if many users are bound to them, causing uneven load.

❓ tradeoff

advanced

Which tradeoff is most relevant when choosing sticky sessions over stateless session management?

Choosing sticky sessions instead of stateless sessions typically trades off:

A Session consistency for reduced fault tolerance and scalability

B Security for faster response times

C Data encryption for easier debugging

D Lower latency for increased storage costs

💡 Hint

Consider how sticky sessions affect system resilience and growth.

Sticky sessions keep session data on one server, which can reduce fault tolerance and scalability compared to stateless designs.

❓ component

expert

In a high-traffic web system using sticky sessions, which approach best ensures session data availability if a server fails?

To maintain session availability despite server failure in a sticky session setup, you should:

A Store sessions only in server memory without replication

B Use a distributed session store accessible by all servers

C Rely solely on the load balancer to redirect traffic to healthy servers

D Disable sticky sessions and use client-side cookies exclusively

💡 Hint

Think about how to keep session data safe and accessible across servers.

A distributed session store allows any server to access session data, preventing loss if one server fails.